# 王磊的作业
# 循环遍历出所有的key
dict = {"k1":"v1","k2":"v2","k3":"v3"}
for i in dict:
    print(i)

#循环遍历出所有的value
for i in dict.values():
    print(i)

#增加一个键值对
dict.update({'K4':'v4'})